|
|
|
|
VOLUME 13(35)Content
ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) THE INFLUENCE OF THE FLOODS UPON THE QUALITIES OF THE WATER MEADOW SOILArvydas Povilas MALIŠAUSKAS, Emilis BALODISSummaryThe influence of the flood upon the density of the water-meadow soil and the quantity of the nutrients in it was investigated in the flood-lands of Nemunas in 1992 - 2000. The quality of the soil was determined in autumn and after the flood in the flooded and unflooded polders as well as in the artificially flooded fields (1994-1996). Long-termed flood did not almost have the effect upon the density of the mineral soil. The density of the peat soil after the flood in the stratum of 0-20cm decreased 7-12 (, but up to the autumn increased anew. The quantity of the hydrolyzed nitrogen after the flood increased at an average: in the mineral soil - 55, peat-soil - 120mg/kg, active phosphorus (P2O5) accordingly 85 and 30 mg/kg, active potassium (K2O) - 20 and 40 mg/kg. The difference between the quantity of nitrogen along the valley was not determined, and the quantity of phosphorus and potassium after the flood in the upper part of the floodlands was accordingly 20 ( and 30 ( bigger than in the delta. The connection between the quantity of the nutrients and duration of flooding was not found. Keywords: flood, polder, meadow, soil, density, quantity of nutrients.
Article received 07 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) SOME RESULTS OF INVESTIGATIONS ON BEAVER EXPANSION INTO DRAINAGE CHANNELSRomanas LAMSODISSummaryMore than 80 % of hydro-graphical network in Lithuania is composed of drainage channels. In this paper an attempt based on the data received by questionnaire method is done to determine the tendencies and measure of beavers (Castor fiber L.), whose population is left to itself, expansion in the drainage channels. The following results were obtained. If beavers had appeared simultaneously in all districts, abundance of population in the whole country at the beginning of their spread into the channels could have amounted to [5947, 9299] (Table 1). At present the part of the population, which is inhabiting drainage channels, exceeds 30 % of total (Table 5). Beaver dams spread in the channels in separate river basins goes away from reintroduction/immigration places chronologically successively (Fig.1). The chance to find beaver dam in the channels is bigger if channel basins are smaller (Fig.7). Besides, there was found out a certain dependence of beaver dam spread in the channels upon geographical surroundings in districts (Fig.2 and 6). Comparative abundance of dams in the channels, which are in forests and outskirts, is ninefold bigger than the one in the fields (Table 4). Reserve of area for beaver-sites to spread in the channels is close to ecologically possible in certain districts. Though in general in most of them there are yet evident possibilities for beaver-site abundance to grow twice and more (Fig.5). Removal of dams, unfortunately, not prevent beavers to inhabit these ones (Table 2). Abbreviations:
Keywords: questionnaire method, abundance, district, geographical surroundings, prognosis.
Article received 09 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) THE FORECASTING OF BED - LOAD TRANSPORT AND BED DEVELOPMENT IN THE LOWER REACHES OF THE RIVER NEMUNASSaulius VAIKASAS, Alfonsas RIMKUS, Antanas DUMBRAUSKASSummaryOn the basis of hydraulic modelling results and water depth measurement data it was investigated the sediment movement mechanics in the 60 km lower of the river Nemunas. It was established that the dynamics equilibrium or river bed formation process is setting in that river section. Only local erosion and sedimentation parts with sand dunes of about 0.3-0.6 m height exists today. By means of mathematical simulation it was also established that in the case of narrowing river with high dikes the bed erosion can could occur. The average depth of this erosion will be about 0.4-0.5 m and new river bed formation process could be delayed for 45-50 year. The additional amount of eroded sand about 15 million m3 as a bed load particles will be settled in the Curronian Lagoon in this case. The average speed of sandy dunes motion Cr was calculated to be 60-65 m/day, an average height (h reaches 0.6-1.1 m and distance of motion is 4 km in the spring flood. The comparison of this data with the experimental 1964 and 2000 year water depth measurement meanings show a satisfactory accordance. Consequently, when compared the data of measurement in 1964-2000 with these of experimental, it could be seen that the measurement meanings of river bed farwater was comparable. Keywords: bed formation process, bed - load, modelling.
Article received 05 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) INFLUENCE OF THE TRANSFORMATIONS OF LAND USE CATEGORIES ON THE CONCENTRATIONS OF NITROGEN AND PHOSPHORUS IN RIVERSHenrikas PAULIUKEVIČIUSSummaryThe structure of land use categories and concentrations of nitrogen and phosphorus in the 46 river-basins have been analysed. The correlation and multiple regression analysis have served as a main tool of investigation. The signs of the regression coefficients have indicated that arable land is a source of N and P, while both wetlands and forests are sinks for N and P. Grasslands are sources of nitrogen and sinks for phosphorus. The concentrations of N total may increase significantly (50 %) when converting wetlands to agricultural area, and 20 % - when converting forests to farming lands. The area of forests and wetlands occupying more than 40% of river-basin area can balance the nitrogen concentrations. Keywords: land use categories of a river basin, nutrients, transformations of land use categories.
Article received 10 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) INVESTIGATION OF THE REASONS OF PHOSPHATES LOAD IN THE RIVER NEVEZISAntanas Sigitas ŠILEIKA, Saulius KUTRA, Laima BERANKIENĖSummaryThe long-term (40 years) observation results of phosphates phosphorus concentration and its load in the river Nevėžis are analised in this article. Amounts and peculiarities of background load, agricultural runoff, and point source pollution from towns (Panevėžys and Kėdainiai) were established for different periods of measurement. It was been obtained that phosphates gets into the river Nevėžis mainly from Kėdainiai (62 %) and Panevėžys (27 %), from agriculture - only up to 7 %, and the background load makes up only 4 %. A considerable agricultural influence was observed only in 1979-1991, when the load increased up to 7-22 kgP/km2 a year and made up 13 % (in 1988), 33 % (in 1984) of the entire amount. This increase of phosphates in the river coincided with the period of the intensive land reclamation. The coefficient of determination was R2=0.72. Reclamation of wetlands made the preconditions for the intensification of agriculture and this could have caused the increase of phosphates flow. After the arrangement of the new drainage systems stopped in 1990, this connection no longer existed. Although the area of reclaimed land did not decreased, the phosphates load started to decrease. For the entire period of investigation, the best relation of the phosphates load from agriculture was obtained with the number of cattle in the basin. The coefficient of determination was R2=0.74. From 1990, when number of cattle started to decrease, the load of phosphates decreased too. Manure handling was not arranged in proper way that is why when number of cattle decreased, the load phosphates decreased too. Now phosphates load from agriculture makes only 2 % of the entire load. Phosphates concentration at Kedainiai still exceeds the permissible concentration in rivers' water 4-9 times. In future, when number of cattle will start to increase, the load of phosphates can increase again. Therefore, it is necessary for all cattle-breeding farms, especially the biggest ones, to establish proper manure pads and slurry reservoirs and to apply it in the periods when there is the least danger for phosphorus leaching. Panevėžys and Kėdainiai are the main polluters of the river Nevėžis with phosphates. Panevėžys increases the load of phosphates in the river on the average 41, while Kėdainiai increase it up to 95 kgP/km2 a year. At present the concentration of phosphates in the reach between Panevėžys and the outlet exceeds the permissible concentration 3.7-9.3 times. In the reach of the river from Panevėžys to the outlet the load of phosphates decreases by 46 % but in the outlet itself water is dangerously polluted with phosphates. The annual phosphates concentration comes up to 0,50 mgP/l or, in other words, exceeds the permissible concentration for 6.2 times. The amount of phosphates getting into the river Nevėžis from Panevėžys and Kėdainiai is so big that concentration of phosphates in the river exceeds permissible concentration for rivers' water but concentration of effluents flowing from these towns still does not exceed the norms for treated effluents flowing into the surface water. As the permissible concentration for the rivers' water is different from that of the effluents, it is legally allowed to pollute river. Those norms should be stricter, or it should be determined the maximum ratio of their load to the river's discharge. Keywords: phosphates, load, concentration, background pollution, agricultural pollution, point source pollution, BPC.
Article received 10 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) THE DEPENDENCE OF PLANT NUTRIENT LEACHING UPON PHYSICAL PROPERTIES OF SOILAngelija BUČIENĖ, Edmundas RAMOŠKA, Danutė LUKIANIENĖSummaryThe reasons of spatial variation of drainage runoff and plant nutrient leaching were examined during four hydrological years on soddy gleic soil in the conditions of rather constant land-use in Valinava experimental site. Among the soil physical properties the thickness of subsoil horizons AB-B and BC-C (r(0.664 and ((0.524, while r95/(95(0.602), the hydraulic conductivity (((0.874) and clay content in arable layer (r(-0.542) mainly influenced on the drainage runoff magnitude. The amount of N leached with drainage runoff was depended on soil non-capilarry porosity of AB-B horizons (((0.614) and clay content (((0.653); phosphorus - on the soil non-capilarry porosity of AB-B horizons (((0.801) and clay content (r(0.698); potassium - on the clay content in Aar and AB-B horizons (((0.750). Keywords: drainage runoff, plant nutrients, leaching, physical properties of the soil, granulation composition, filtration coefficient, subsoil.
Article received 10 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Institute of Water Management, 2000 vol. 13(35) AUTONOMIZATION OF DRAINAGE SYSTEMS WHICH ARE IN FARMERS' LANDAloyzas STIRKASummaryBig drainage systems are not perspective in different aspects (agricultural, technical and ecological), therefore in the future they must be divided into smaller autonomous parts (so that their area was in one farmer's land) and in such way it must be achieved as big autonomy degree as possible which is characterized by autonomy drainage system area part (%) falling on the whole drained area of one farmer's land. Trying to find out the autonomous extent and the autonomy possibilities of the drainage systems which are in farmers' plots, investigations were made in 118 new-founded farmers' lands, the total area of which was 1023, 69, in Kėdainiai and Dotnuva districts. The investigations had shown that the autonomous extent of the drainage systems which were in those farmers' land makes up only 26 % on the average. The autonomous extent depends not only on the drainage systems, but on the size of farmers' plots as well. It has been established that in plots of land less than 5 ha the autonomous extent of drainage systems hardly reaches 8.4 %, while in the plots of land bigger than 10 ha the autonomy increases up to 33 %. The investigations had shown that the arrangement of autonomy means in the drainage systems which are in farmers' land would cost 110 Lt/ha, and the autonomy of these drainage systems would increase up to 79 %. The autonomous extent of big drainage systems which are farmers' plots of land may be increased by dividing those systems into smaller autonomous parts. Meanwhile the rightest means is dividing of drainage systems by laying extra pick-ups. Arranging the autonomy means it must be taken into account that the conditional expenses must not be bigger than the reclamation profit share given to agriculture: this would make about 10-30 % of the common agricultural profit. The advantages of the drainage systems which are in farmers' plots of land are as follows: - it is possible to observe permanently the function of drainage and in such way to guarantee the preventive disclosing of defects and to maintain the desirable water regime in drained area; - it is possible to localize the deterioration consequences of drainage systems and at the same time to stop the pollutant migration from drained farming lands. Keywords: farmers plots of land, drainage systems, autonomous extent, autonomy means.
Article received 10 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute for Water Management 2000 vol. 13(35) INVESTIGATION SAND FILTER, PLANT-GROUND FILTER AND ANAEROBIC TREATMENT EQUIPMENTAlbinas KUSTA, Renė KUSTIENĖ, Midona DAPKIENĖSummaryThe article analyses the problem of small wastewater treatment equipment in the rural areas of Lithuania. The aim of the investigations is to determine the efficiency of wastewater treatment equipment, used in the rural areas, and to establish the possibilities of using this equipment under different conditions. Treatment equipment of three types - sand filter of vertical filtration, plant - ground filter and reconstructed anaerobic treatment equipment - underwent a detailed investigation. The obtained results show that household wastewater is effectively treated by sand filter of vertical filtration and sufficiently well - by plant-ground filter. Exploitation of both types of filters is simple and cheap, but installation requires significantly bigger plots of land in comparison with aeration equipment. The investigated anaerobic wastewater treatment equipment, which had been reconstructed from aerotanks, did not justify itself completely as the required level of wastewater treatment was not reached. Keywords: sand and plant-ground filter, anaerobic equipment.
Article received 07 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute for Water Management 2000 vol. 13(35) THE ECONOMICAL AND ECOLOGICAL ESTIMATION OF STRUCTURE OF CROPS IN CROP ROTATIONGinutis KUTRA, Ramutė AKSOMAITIENĖSummaryIn this article the income and expenditure change dynamics and its influence on environment are analysed by growing crops of different structure in five crop rotation fields. The analysis was made on the base of production income and expenditure, plant nutritious matter balances and the data of leached nutritious matter together with the drainage runoff. The most profitable rotation was the one where sugar beet prevailed (55 % of the crop), although ecologically it was one of the worst variants - the amount of leached mineral nitrogen was about 63.7 kg/ha. In the crop structure variant which was the worst one economically (profitableness - 3), when cereals were sown year by year, the amount of leached nitrogen was almost two times bigger to compare with the amount of it when cereals were alternated with other plants. When perennial grass was included into rotations the leaching decreased most efficiently. The graphs of income and expenditure dependence upon quantity of nitrogen fertilizers show that the increasement of fertilizers correlate with the expenditure increasement for production (regression coefficient 14), but the incoming profits increased more quickly (regression coefficient 19.2). Nitrogen balances and leaching researches show that extending the amounts of fertilizers the leaching increases as well, therefore it must be achieved that the amount of nutritious matter getting into the soil together with fertilizers would not exceed the amount of it which is necessary for plants to grow. In order to choose plants for crop rotation, maximizing profits, we offer to apply the restriction because of the possible negative impact on environment. On the conditions of our investigation, when monoculture was cereals, the coefficient expressing profit restriction would be 0.48; and having extend sugar beet areas up to 50 % the profit restriction coefficient would be 0.63. Keywords: income, expenditure, balance of nutrients, leaching.
Article received 10 2000, given to print 12 2000. ISSN 1392-2335 Transactions of the Lithuanian University of Agriculture and Lithuanian Institute for Water Management 2000 vol. 13(35) THE ENVIRONMENTAL PROTECTION ASPECTS OF DISTILLERY REFUSE USAGE IN FIELD FERTILIZATIONGediminas SARGŪNAS, Audrius DILBA, Zenonas STRUSEVIČIUSSummaryIn this article the investigation results of the usage of joint-stock company "Sema" distillery refuse in the agricultural fertilization are given. The outside experiments were made in the cultivated loamy soil which was typical in the district of Panevėžys. In the time of investigation the traditional cultures of crop rotation were grown: barley, wheat, potatoes, sugar beet, perennial grass. The investigated distillery refuse produced by "Sema" is the high-quality organic fertilizers saturated with potassium and containing the microelements necessary for the soil. The amount of heavy metals in the distillery refuse is not big, in fact it is close to the amount of it in the natural environment. The fresh distillery refuse is sterile and contains quite many proteins, that is why it is good for feeding. The outside experiments were made in the period of three hydrological years from November 1996 till October 1999. In the period of investigation the amount of precipitation of every separate year was different - from 76.2 % till 150 % of the perennial mean. Such conditions made possible to estimate the impact on environment by fertilizing with distillery refuse in dry years as well as in rainy years. In the fields fertilized with different amount of distillery refuse the different flow of biogenic substances from the root zone (0-50 cm) was established: increasing the amount of fertilizers the quantity of biogenic substances leached into environment increased as well. In the fields fertilized with more than 50 t/ha of distillery refuse the free drainage water was periodically unpermittedly polluted with biogenic elements (nitrogen and potassium), therefore there was a danger to pollute drainage and underground water. In five investigated variants (1 - control, not polluted; 2, 3, 4, 5 - polluted with distillery refuse accordingly 50, 100, 200 and 400 t/ha) big differences of vegetable yield were however, the most efficient impact of distillery refuse the soil receives 215-280 kg/ha of nitrogen, 5-8 kg/ha of phosphorus and 400-750 kg/ha of potassium fertilizers. In the directives of the European Union and in the normative documents of the Environment of Lithuania the annual amount of organic fertilizers after nitrogen is limited up to 210 kg/ha. Therefore the amount of distillery refuse after nitrogen - 50 t/ha - is acceptable. When the annual norm of distillery refuse in 50 t/ha the accumulation of active potassium in the soil increases every year, because the quantity of potassium carried out with plants is much less than the annual quantity of it carried into the soil. Therefore it is better to use distillery refuse in the same field every two years in order to avoid the over fertilization of soil with potassium. Making the complex estimation of the impact of distillery refuse on the fertility and quality of plants, on the change of agrochemical characteristics of soil and on the flow of biogenic substances into the environment, the economically and ecologically acceptable norm of fertilization with distillery refuse is 50 t/ha. Keywords: distillery refuse, fertilization rates, nutrients, quality of plants.
Article received 10 2000, given to print 12 2000.
|
|
